Conclusion This series of investigations demonstrated how we can apply our knowledge to improve the treatment outcome of ESWL. Based on clinical information, such as age, suitable candidates for ESWL can be identified, and hence better application of ESWL can be achieved. With an understanding of the benefits and limitations of imaging (NCCT and intravenous urography), treatment success can be predicted, and better treatment plans for patients can be formulated. A policy of more liberal use of analgesia during ESWL can also help to improve the treatment outcomes of patients. Finally, with the use of different assessment methods, the true impact of various new technologies or treatment protocols can be assessed, and the results can lead to better understanding of ESWL and also improvement in the treatment outcomes. / Materials and Methods In a retrospective review of treatment information of 2192 patients, the effect of age on stone-free rates after ESWL was assessed. Next, in a prospective study, the role of stone parameter, measured using non-contrast computerized tomography (NCCT), in predicting the treatment outcomes of upper ureteric stones was examined. The general applicability of caliceal pelvic height (CPH) in determining the treatment outcomes for lower caliceal stones for three different lithotriptors was assessed in the third study. In another retrospective comparative study, the effect on treatment outcomes of additional usage of intravenous analgesic during ESWL, as compared to oral analgesic premedication alone, was analyzed. Finally, the feasibility of the use of two statistical methods, logistic regression and matched-pair analysis, in comparing the treatment results of different lithotriptors was investigated. / Objectives Despite the initial success of extracorporeal shock wave lithotripsy (ESWL), the performance of the contemporary machines has never been as good as that of the first-generation machine. Therefore, a series of studies was conducted to advance the current knowledge of ESWL and investigate possible ways to further optimize the treatment outcomes. / Results We found that the stone-free rate after ESWL for older patients with renal stones, but not for those with ureteric stones, was significantly lower than that of younger patients. Stone parameters measured using NCCT, namely, mean stone density, stone volume, and skin-to-stone distance, were significant predictive factors for successful ESWL for upper ureteric stones. However, caliceal pelvic height, measured by intravenous urography, was a significant predictor of treatment outcomes of lower caliceal stones for only the Piezolith 2300 lithotriptor, and not the other two types of lithotriptors. The additional usage of intravenous analgesic improved the effectiveness quotient and hence treatment outcomes of ESWL. Finally, both logistic regression and matched-pair analysis were found to be feasible approaches for the comparison of the performance of different lithotriptors. / Chi-Fai Ng. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 224-243). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.

Made available in DSpace on 2014-06-11T19:31:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-27Bitstream added on 2014-06-13T21:02:10Z : No. of bitstreams: 1 pyles_md_dr_botfmvz.pdf: 1285768 bytes, checksum: c7e043fd85c25b169c8a9bb3a6e24772 (MD5) / Universidade Estadual Paulista (UNESP) / O objetivo deste estudo foi avaliar os efeitos da aplicação de ondas de choque extracorpóreas no osso terceiro metacarpiano de equinos hígidos através da determinação da elasticidade óssea. Para tanto, foram utilizados 20 equinos da raça Puro Sangue Inglês, machos e fêmeas, com dois anos de idade, clinicamente sadios e em início de treinamento, sendo selecionados quanto ao estado de higidez com especial atenção quanto à integridade do aparelho locomotor. No D0, dia zero do experimento, todos os animais foram submetidos à avaliação da elasticidade óssea realizada no osso terceiro metacarpiano. Os animais foram divididos aleatoriamente em dois grupos de dez animais em cada (Grupo Controle e Grupo Tratamento). A aplicação da terapia com ondas de choque extracorpóreas (ESWT) foi realizada no membro torácico direito dos animais do Grupo Tratamento, na região coincidente à da avaliação da elasticidade óssea e para tanto foi utilizado aparelho para terapia de ondas extracorpóreas com densidade de fluxo de energia de 0,15 mJ/mm2 e 2000 pulsos com sonda E6R20, com a característica do foco da onda de choque de 20mm. As aplicações da ESWT foram repetidas a cada 21 dias totalizando três sessões (D0, D21 e D42). A análise da determinação da elasticidade óssea, além do D0, foi realizada no 21o dia após a primeira aplicação, no 21o dia após a segunda aplicação e no 30o dia após a terceira aplicação de ESWT (D21, D42 e D72). A média da velocidade ultrassonográfica (SOS) diferiu entre os grupos no D21, D42 e D72, sendo que os animais do Grupo Tratamento apresentaram menor densidade mineral óssea após as aplicações da ESWT. Houve diferença também à análise da massa óssea (Z-Score) entre os grupos no D21 e D42, quando... / The purpose of this study was to evaluate the effects of extracorporeal shock waves in third metacarpus bone from healthy horses by determination of bone elasticity. It were used 20 Thoroughbred horses, male and female, with two years old, clinically healthy and on top of training, selected as healthy state and special attention on the integrity of the locomotor system. At D0, day zero of the experiment, all animals were submitted to evaluation of bone elasticity held in the third metacarpus bone. The animals were randomly divided into two groups of ten animals (Control Group and Treatment Group). The application of extracorporeal shock wave therapy (ESWT) was performed on the right forelimb of the animals in the Treatment group in the same location evaluated for bone elasticity and extracorporeal therapy of waves was applied with 0.15mJ/mm2 energy flux density and 2000 pulses with E6R20 probe, with focus feature of the shock wave of 20mm. The applications of ESWT were repeated every 21 days, a total of three sessions (D0, D21 and D42). The analysis of bone elasticity determination was realized at D21, D42 and D72. The average speed ultrasound (SOS) differed between groups at D21, D42 and D72, and the animals from treatment group had lower bone mineral density after applications of ESWT. There was also difference in the analysis of bone mass (Z-Score) between the groups at D21 and D42, where animals from treatment group showed a significant decrease in bone mass. The risk of fracture were higher in animals from treatment group at D21. It was concluded that ESWT is able to promote change in bone mineral density.

Este trabalho experimental tem por objetivo apresentar os estudos experimentais realizados com jatos de líquidos evaporativos (\"flash boiling\") de iso-octano. Nos estudos, o jato emergia de um diminuto bocal que descarrega em uma grande câmara de baixa pressão. O líquido ao passar pelo bocal sofria uma expansão interna alcançando elevados graus de superaquecimento ou de metaestabilidade, já que se mantinha na fase líquida. Nos experimentos, eram controladas as condições de pressão e temperatura de injeção durante um período de alguns poucos segundos suficientes para que as condições de regime permanente fossem estabelecidas. Um dos métodos para a visualização do escoamento do jato evaporativo foi o \"Schlieren\", o qual permitia visualizar elevados gradientes de densidade como normalmente ocorrem com ondas de choque, presentes nesta investigação. Também foi empregada a técnica de visualização de \"iluminação por detrás\" para que fossem comparadas as imagens obtidas por este método com o do \"Schlieren\", bem como mostrar detalhes do fenômeno em estudo. Com isso, foi possível estudar a estrutura do processo evaporativo do jato e, com o auxílio de ferramentas de filtragem matemática e manipulação das imagens obtidas, os fenômenos compressíveis envolvidos. Os perfis dos jatos observados foram: (1) filete contínuo de líquido sem evaporação, (2) jato com fragmentações ou atomizado e (3) abrupta evaporação seguida por expansão com formação de ondas de choque. Neste último caso, a inspeção das fotografias indicou que a evaporação do líquido se dava externamente ao bocal, a partir de um núcleo metaestável de líquido, o qual apresentava o formato aproximado de um cone. Também foi aplicada a teoria de ondas oblíquas de evaporação para estudar o comportamento deste cone líquido. Os ensaios foram conduzidos com três bocais cônico-convergentes de dimensões e materiais diferentes, quais sejam: bocal de aço com diâmetro de saída de 0,3 mm, bocal de aço com 0,8 mm e bocal de vidro com 0,35 mm. / The main goal of this thesis is to present results of experiments with flashing liquid jets of iso-octane. The experiments were carried out with a liquid jet issuing from a small nozzle into a low-pressure chamber. High degrees of metastability were obtained as the liquid jet expanded within the nozzle. Injection pressure and temperature were controlled to the desired testing values for a few seconds, which were found long enough to reach and keep the steady state regime. The photographic documentation of the phenomenon was obtained from a \"Schlieren\" set up using CCD camera. The \"back-lightening\" visualization technique was also used in order to compare both image techniques and to unveil some flashing phenomenon details. Analyses of these images with the help of mathematical filters as well as other image manipulating techniques enabled a qualitative visualization of the flashing liquid jet structure and geometry leaving the nozzle. Three liquid jet regimes were observed: (1) continuous liquid jet (2) partially atomized, and (3) evaporation with the presence of shock waves. In this latter case, we speculate that the evaporation took part on the liquid jet surface, which had the approximate shape of a cone. Also it was employed the oblique evaporation wave theory to explain some of the behavior of the overall evaporation process. The tests were carried out using three conical-converging nozzles made of different materials: a 0.3 mm exit diameter steel nozzle, a 0.8 mm exit diameter steel nozzle, and a 0.35 mm exit diameter glass nozzle.

A comprehensive understanding of high-speed liquid jets is required for their introduction into engine and combustion applications. Their transient nature, short lifetime, unique characteristics and the inability to take many experimental readings, has inhibited this need. This study investigates the outflow of a high-speed liquid jet into quiescent atmospheric air. The key characteristics present are, a bow shock wave preceding the jet head, an enhanced mixing layer and the transient deformation of the liquid jet core. The outflow regime is studied in an experimental and numerical manner. In the experimental investigation, a high-speed liquid water jet is generated using the momentum exchange by impact method. The jet velocity is supersonic with respect to the impinged gaseous medium. The resulting jet speed is Mach 1.8. The jet is visualised with the use of shadowgraph apparatus. Visualisation takes place over a variety of time steps in the liquid jet???s life span and illustrates the four major development stages. The stages progress from initial rapid core jet expansion to jet stabilisation and characteristic uniform gradient formation. The visualisation shows that at all stages of the jet???s life it is axi-symmetric. One dimensional nozzle analysis and a clean bow shock wave indicate that the pulsing jet phenomenon can be ignored. In the numerical investigation, a time marching finite volume scheme is employed. The bow shock wave characteristics are studied with the use of a blunt body analogy. The jet at a specific time frame is considered a solid body. The jet shape is found to have an important influence on the shock position and shape. Analysis of the results indicates a shock stand-off similar to that seen in experimental observations and the prediction of shock data. The jet life span is modelled using a species dependent density model. The transient calculations reproduce the key jet shape characteristics shown in experimental visualisation. The mushrooming effect and large mixing layer are shown to develop. These effects are strongest when the shock wave transience has yet to stabilise. Quantitative analysis of the mixing layer at varying time steps is presented.

The generalized theory of thermoelasticity was employed to characterize the coupled thermal and mechanical wave propagation in high performance microelectronic packages. Application of a Gaussian heat source of spectral profile similar to high performance devices was shown to induce rapid thermal and mechanical transient phenomena. The stresses and temporal gradient of stresses (power density) induced by the thermal and mechanical disturbances were analyzed using the Gabor Wavelet Transform (GWT). The arrival time of frequency components and their magnitude was studied at various locations in the package. Comparison of the results from the classical thermoelasticity theory and generalized theory was also conducted. It was found that the two theories predict vastly different results in the vicinity of the heat source but that the differences diminish within a larger time window. Results from both theories indicate that the rapid thermal-mechanical waves cause high frequency, broadband stress waves to propagate through the package for a very short period of time. The power density associated with these stress waves was found to be of significant magnitude indicating that even though the effect, titled short time scale effect, is short lived, it could have significant impact on package reliability. The high frequency and high power density associated with the stress waves indicate that the probability of sub-micron cracking and/or delamination due to short time scale effect is high. The findings demonstrate that in processes involving rapid thermal transients, there is a non-negligible transient phenomenon worthy of further investigation.

<p>In this dissertation work, the aim was to garner better mechanistic understanding of how shock wave lithotripsy (SWL) breaks stones in order to guide design improvements to a modern electromagnetic (EM) shock wave lithotripter. To accomplish this goal, experimental studies were carefully designed to isolate mechanisms of fragmentation, and models for wave propagation, fragmentation, and stone motion were developed. In the initial study, a representative EM lithotripter was characterized and tested for in vitro stone comminution efficiency at a variety of field positions and doses using phantom kidney stones of variable hardness, and in different fluid mediums to isolate the contribution of cavitation. Through parametric analysis of the acoustic field measurements alongside comminution results, a logarithmic correlation was determined between average peak pressure incident on the stone surface and comminution efficiency. It was also noted that for a given stone type, the correlations converged to an average peak pressure threshold for fragmentation, independent of fluid medium in use. The correlation of average peak pressure to efficacy supports the rationale for the acoustic lens modifications, which were pursued to simultaneously enhance beam width and optimize the pulse profile of the lithotripter shock wave (LSW) via in situ pulse superposition for improved stone fragmentation by stress waves and cavitation, respectively. In parallel, a numerical model for wave propagation was used to investigate the variations of critical parameters with changes in lens geometry. A consensus was reached on a new lens design based on high-speed imaging and stone comminution experiments against the original lens at a fixed acoustic energy setting. The results have demonstrated that the new lens has improved efficacy away from the focus, where stones may move due to respiration, fragmentation, acoustic radiation forces, or voluntary patient movements. Using traditional theory of brittle fragmentation and newfound understanding of average peak pressure correlation to stone comminution, the entire set of stone comminution data for lens comparison was modeled using a Weibull-style distribution function. This model linked both the average peak pressure and shock wave dose to efficacy, including their respective threshold parameters, and demonstrated correlation of coefficients to cavitation activity. Subsequently, this model was used in prediction of stone comminution efficiency from mimicked respiratory motions in vitro, which compared favorably to actual simulated motion studies using both the new and original lenses. Under a variety of mimicked respiratory motions, the new lens produced statistically higher stone comminution efficiency than the original lens. These results were confirmed in vivo in a swine model, where the new lens produced statistically higher stone comminution after 1,000 and 2,000 shocks. Finally, a mechanistic investigation into the effects of cavitation with the original lens was conducted using an integrated, self-focusing annular ring transducer specially designed for tandem pulse lithotripsy. It was found that cavitation and stone comminution efficiency are progressively enhanced by tandem pulsing as source energies of both the primary LSW and trailing pressure pulse increase, which suggests cavitation and stress waves act synergistically enhance the efficacy in kidney stone fragmentation.</p> / Dissertation

No description available.

No description available.

In the current research, a framework based on classical molecular dynamics (MD) is developed for computational mechanical analyses of complex nanoscale materials. The material system of focus is a combination of fcc-Al and and #945;-Fe₂O₃. The framework includes the development of an interatomic potential, a scalable parallel MD code, nanocrystalline composite structures, and methodologies for the quasistatic and dynamic strength analyses. The interatomic potential includes an embedded atom method (EAM) cluster functional, a Morse type pair function, and a second order electrostatic interaction function. The framework is applied to analyze the nanoscale mechanical behavior of the Al+Fe₂O₃ material system in two different settings. First, quasistatic strength analyses of nanocrystalline composites with average grain sizes varying from 3.9 nm to 7.2 nm are carried out. Second, shock wave propagation analyses are carried out in single crystalline Al, Fe₂O₃, and one of their interfaces. The quasistatic strength analyses reveal that the deformation mechanisms in the analyzed nanocrystalline structures are affected by a combination of factors including high fraction of grain boundary atoms and electrostatic forces. The slopes as well as the direct or inverse nature of observed Hall-Petch (H-P) relationships are strongly dependent upon the volume fraction of the Fe₂O₃ phase in the composites. The compressive strengths of single phase nanocrystalline structures are two to three times the tensile strengths owing to the differences in the movement of atoms in grain boundaries during compressive and tensile deformations. Analyses of shock wave propagation in single crystalline systems reveal that the shock wave velocity (US) and the particle velocity (UP) relationships as well as the type and the extent of shock-induced deformation in single crystals are strongly correlated with the choice of crystallographic orientation for the shock wave propagation. Analyses of shock wave propagation through an interface between Al and Fe2O3 point to a possible threshold UP value beyond which a shock-induced structural transformation that is reactive in nature in a region surrounding the interface may be taking place. Overall, the framework and the analyses establish an important computational approach for investigating the mechanical behavior of complex nanostructures at the atomic length- and time-scales.

The enforcement of national health insurance brings the new transition of medical service. The main purpose of this study is to investigate patients¡¦ emphasis and satisfaction on different dimension of service quality. The study referred to industrial views, related literature review and 5Qs model (Zineldin, 2006). Eventually, the practical research results are used to conduct a competitive niche strategy and a positioning plan of extracorporeal shock wave lithotripsy market to seek the unique value of medical service differentiation. According to the empirical view, the satisfaction and loyalty of those patients who had operations under the hospital treatment were significantly higher than those patients who didn¡¦t. ¡§Quality of atmosphere¡¨ and ¡§Quality of infrastructure¡¨ were the two factors which had positive impact on the satisfaction of patients. Also, ¡§Quality of medical care interaction¡¨ and ¡§Quality of atmosphere¡¨ affected the loyalty of patients greatly. Therefore, this study suggested that doctors should provide professional medical services to offer unique attributes which were valued by patients, and then achieved the influence of word-of-mouth marketing. The Competitive strategy is (1) from standardization to differentiation: creating values to patients by standard operation procedure. (2) from selfish departmentalism to patient-orientation: providing more interactions during medical service to fulfill the cognitive and emotional needs of patients. (3) from tradition to innovation: carrying out a new model which was designed by whole new ideas to supply medical service with sustainable competitive advantage. (4) from closed to open environment: emphasizing on profession and abandoning asymmetric information to develop trust relationship between doctors and patients. The strategic positioning of ESWL is to provide cordial, effective and fast integrated medical service for patients, and the establishment of ¡§Shock Wave Lithotripsy Center¡¨ is the further step of this strategy.